Design principles for maximizing photovoltage in metal-oxide-protected water-splitting photoanodes
Design principles for maximizing photovoltage in metal-oxide-protected water-splitting photoanodes
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DOI：
10.1038/nmat4451
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发表时间：
2016-01-01
期刊：
影响因子：
41.2
通讯作者：
McIntyre, Paul C.
中科院分区：
文献类型：
--
作者：
Scheuermann, Andrew G.;Lawrence, John P.;McIntyre, Paul C.
用于光阳极的金属氧化物保护层可以实现大规模太阳能燃料和太阳能化学合成的发展，但迄今为止经常报道的较差的光电压将严重限制其性能。在这里，我们报告了一个新的观察与保护层施加的电荷提取势垒相关的光电压损失，并通过消除它，实现高达630 mV的光电压，最大的水裂解硅光阳极迄今为止报道。系统地探讨了金属-绝缘体-半导体肖特基结电池相比，掩埋结p（+）n电池的损耗机制，揭示了需要保持在半导体/绝缘体界面的特征空穴密度。与保护氧化物的介电特性相关的漏电容模型解释了这种损失，与数据吻合得很好。根据这些发现，我们制定了设计原则，同时优化内置场，界面质量和孔提取，以最大限度地提高氧化物保护的水裂解阳极的光电压。
Metal oxide protection layers for photoanodes may enable the development of large-scale solar fuel and solar chemical synthesis, but the poor photovoltages often reported so far will severely limit their performance. Here we report a novel observation of photovoltage loss associated with a charge extraction barrier imposed by the protection layer, and, by eliminating it, achieve photovoltages as high as 630mV, the maximum reported so far for water-splitting silicon photoanodes. The loss mechanism is systematically probed in metal-insulator-semiconductor Schottky junction cells compared to buried junction p(+) n cells, revealing the need to maintain a characteristic hole density at the semiconductor/insulator interface. A leaky-capacitor model related to the dielectric properties of the protective oxide explains this loss, achieving excellent agreement with the data. From these findings, we formulate design principles for simultaneous optimization of built-in field, interface quality, and hole extraction to maximize the photovoltage of oxide-protected water-splitting anodes.